The plant St. John's Wort as well as its applicability as a pharmaceutical were already known to people of antiquity. Most of the approximately 370 species of this plant worldwide comprise the red pigment hypericin, a naphthodianthrone derivative having a molecular weight of 504.43 and the empirical formula C.sub.30 H.sub.16 O.sub.8. In addition to hypericin, a number of structural analogs was identified which have been described in the literature as pseudohypericin, protohypericin, protopseudohypericin, cyclopseudohypericin, isohypericin, Kielcortin etc., so-called polycyclic diones. Other components of the plant are, for example, the flavonoid quertecine as well as other bioflavonoids and flavonoid glycosides, vegetable acids such as chlorogenic and coffeic acid, hyperforin--a phloroglucine derivative--tanning agents, flower pigments as well as cyanidin chloride and xantophyll, anthraquinone, xanthone derivatives, distilled oils such as terpineol, resin-like substances, fats and waxes.
It has recently been found that polycyclic diones (hypericin, pseudohypericin and/or salts thereof) in highly pure form have antiviral efficacy. In particular, an inhibiting effect on retrovirus can be observed in vitro (cf. EP 0 332 697 B1); this applies also with respect to the human immunodeficiency virus (HIV) which in humans causes the acquired immune deficiency syndrome (AIDS). Hypericin or pseudohypericin were herein used in highly pure form. In order to obtain this form, the extract from the plant Hypericum was treated until nearly pure hypericin/pseudohypericin was obtained. Alternatively, highly pure hypericin was produced synthetically. The medications suggested in this connection comprised nearly pure hypericin/pseudohypericin (or pharmaceutically efficacious salts thereof) as the sole active agent, and, in addition, pharmacologically known solvents and carrier substances suitable in known manner for various forms of administration and dosages.
It has also been suggested to combine for the treatment of diseases caused by retrovirus the administration of hypericin/pseudohypericin with the administration of nucleoside analogs WO 89/09056. However, herein also nearly pure hypericin/pseudohypericin was used.
However, animal experiments have shown that when using highly pure hypericin/pseudohypericin, strong side effects in the form of hyperphotosensitization can occur. Due to this effect, the therapeutic application of preparations with highly pure hypericin/pseudohypericin must be ruled out. Therefore, this approach has not been pursued further and no Hypericum preparations for antiviral application have been introduced on the market.
In addition, in the field of medicine, Hypericum preparations have long been used based on extracts of the plant for various indications in the psychogenic area such as depressions in the absence of endogenous forms, sleep disorders and psychogenically caused other disorders such as bed wetting. An oily preparation from the plant (oleum hypericin) for external application in the treatment of wounds and pain is additionally known. The internal application of oleum hypericin has been recommended in the case of dyspeptic complaints.
The currently valid monograph by the Kommission E of the Bundesamt fur Arzneimittel und Medizinprodukte (Federal Board for Pharmaceutical Drugs and Medical Products) lists as fields of application psychovegetative disorders, depressive states, anxiety and/or nervous agitation. All currently known Hypericum-containing pharmaceutical drugs concern this range of indications of psychogenic disorders and sleep disorders.
The known Hypericum-containing pharmaceutical drugs are based on the extract from the plant with a content of polycyclic diones (hypericin, pseudohypericin and/or salts thereof) of less than 1%. The listed active agents are thus not present in a pure state. The use of such preparations for the indications in viral illnesses is not known.
This range of indications had previously only been suggested for highly pure hypericin/pseudohypericin preparations but which, due to the above cited side effects, cannot be used therapeutically.